The ACC/PAS + LKA combo gives you almost self-driving capabilities, that while not completely replacing the driver, gives you a huge boost in security.
First, ACC keeps a constant speed AND distance set by you. Then the vehicle just accelerates and/or brakes to adjust to varying traffic conditions. It works just as expected, and is able to react in an instant if the vehicle in front of you suddenly brakes, or someone cuts in front of you.
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Now, one of the least liked options -or so it seems- is LKA. Yes, it does feel different driving with LKA, but if needed, the car will actually keep you in your lane, even if you are in a curve.